The display-control interface

doc
1

display-control allows configuring display parameters such as brightness.

Auto-connect: no

Requires snapd version 2.37+.`

ⓘ This is a snap interface. See Interface management and Supported interfaces for further details on how interfaces are used.

2

If I understand it correctly, the display-control interface (among other things) grants access to org.gnome.SettingsDaemon.Power.Screen object via methods StepDown and StepUp.

I wonder why reading of the “Brightness” property is prohibited for the respective interface? This would imply having something like

dbus (send)
  bus=session
  path=/org/gnome/SettingsDaemon/Power
  interface=org.freedesktop.DBus.Properties
  member="Get{,All}"
  peer=(label=unconfined),

in the apparmor profile, is that possible?